/Engine/Source/Runtime/Datasmith/CADKernel/Public/CADKernel/Core/Session.h
To be consistent, all entity to save have to had an Id. This method browses all sub entities and set their Id if needed
uint32 SpawnEntityIdent ( [FEntity](API\Runtime\CADKernel\CADKernel\Core\FEntity) & SelectedEntity, bool bForceSpawning )